Major element residence times in humus from a beech forest: The role of element forms and recycling

This study presents the relationship between inputs of elements (especially biominerals), their recycling mechanisms and the average residence time of the major elements in mull humus.In forest ecosystems with generally low element inputs, decomposing leaf litter is an important source of soil nutrients. While the processes and the release speeds of elements, such as C, N and P, are well determined during litter degradation, less is known about elements like Fe, Al, Mg, Mn, Si, Ca, K, or Na, some of which are essential for tree nutrition.The objective of this study was to determine the average residence time of these elements in mull-type humus for 3 different soils: a Dystric Cambisol (S1), Eutric Cambisol (S2) and Rendzic Leptosol (S3), in the same beech grove of the northeast of France and to identify the main mechanisms controlling them.To achieve this goal, the approach used: 1) scanning electron microscope observation of the evolution and recycling of elements during litter degradation; 2) quantification of total inputs and their form (soluble/insoluble) in the litterfall and the contribution of exploitation residues; 3) quantification and evolution of litter stocks; and 4) calculation and comparison of the residence time of the elements according to their form.Calculation of inputs and stocks of elements in humus made it possible to assess the residence time of each elements. The average residence times were between 58.4 and 13.1 y for Fe and Al; 3.3 and 1.6 y for ...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research